A clutch of

eggs An egg is an organic vessel in which an embryo begins to develop. Egg, EGG or eggs may also refer to: Biology * Egg cell, the female reproductive cell (gamete) in oogamous organisms Food * Eggs as food Places * Egg, Austria * Egg, Switzerland ...

is the group of eggs produced by

birds Birds are a group of warm-blooded vertebrates constituting the class (biology), class Aves (), characterised by feathers, toothless beaked jaws, the Oviparity, laying of Eggshell, hard-shelled eggs, a high Metabolism, metabolic rate, a fou ...

amphibians Amphibians are ectothermic, anamniote, anamniotic, tetrapod, four-limbed vertebrate animals that constitute the class (biology), class Amphibia. In its broadest sense, it is a paraphyletic group encompassing all Tetrapod, tetrapods, but excl ...

, or

reptiles Reptiles, as commonly defined, are a group of tetrapods with an ectothermic metabolism and Amniotic egg, amniotic development. Living traditional reptiles comprise four Order (biology), orders: Testudines, Crocodilia, Squamata, and Rhynchocepha ...

, often at a single time, particularly those laid in a

nest A nest is a structure built for certain animals to hold Egg (biology), eggs or young. Although nests are most closely associated with birds, members of all classes of vertebrates and some invertebrates construct nests. They may be composed of ...

. In birds, destruction of a clutch by

predator Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common List of feeding behaviours, feeding behaviours that includes parasitism and micropredation ...

s (or removal by humans, for example the

California condor The California condor (''Gymnogyps californianus'') is a New World vulture and the largest North American land bird. It became extinct in the wild in 1987 when all remaining wild individuals were captured, but has since been reintroduced to n ...

breeding program) results in ''double-clutching''. The technique is used to double the production of a species' eggs, in the California condor case, specifically to increase population size.

Size

Clutch size differs greatly between

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

, sometimes even within the same

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

. It may also differ within the same

due to many factors including

habitat In ecology, habitat refers to the array of resources, biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species' habitat can be seen as the physical manifestation of its ...

, health, nutrition, predation pressures, and time of year. Clutch size variation can also reflect variation in optimal reproduction effort. In birds, clutch size can vary within a species due to various features (age and health of laying female, ability of male to supply food, and abundance of prey), while some species are determinant layers, laying a species-specific number of eggs. Long-lived species tend to have smaller clutch sizes than short-lived species (see also selection theory). The evolution of optimal clutch size is also driven by other factors, such as

parent–offspring conflict Parent–offspring conflict (POC) is an expression coined in 1974 by Robert Trivers. It is used to describe the evolutionary conflict arising from differences in optimal parental investment (PI) in an offspring from the standpoint of the parent an ...

. In birds, ornithologist

David Lack David Lambert Lack FRS (16 July 1910 – 12 March 1973) was a British evolutionary biologist who made contributions to ornithology, ecology, and ethology. His 1947 book, ''Darwin's Finches'', on the finches of the Galapagos Islands was a land ...

carried out much research into regulation of clutch size. In species with altricial young, he proposed that optimal clutch size was determined by the number of young a parent could feed until fledgling. In precocial birds, Lack determined that clutch size was determined by the nutrients available to egg-laying females. An experimental study in brant geese (''

Branta bernicla The brant or brent goose (''Branta bernicla'') is a small goose of the genus ''Branta''. There are three subspecies, all of which winter along temperate-zone sea-coasts and breed on the high-Arctic tundra. The Brent oilfield was named after ...

''), which rarely lay more than five eggs, found that the probability of an egg successfully leading to a fledged gosling declined from 0.81 for two-egg clutches to 0.50 for seven-egg clutches, whilst the nesting period increased with the increasing number of eggs laid. This suggests that there is no benefit for female brant geese to lay more than five eggs.

Gallery

Image:Anas platyrhynchos (nest).JPG,

Mallard The mallard () or wild duck (''Anas platyrhynchos'') is a dabbling duck that breeds throughout the temperate and subtropical Americas, Eurasia, and North Africa. It has been introduced to New Zealand, Australia, Peru, Brazil, Uruguay, Arge ...

(''Anas platyrhynchos''), very large clutch or possibly from two females Image:Larus marinus eggs.jpg,

Great black-backed gull The great black-backed gull (''Larus marinus'') is the largest member of the gull family. It is a very aggressive hunter, pirate, and scavenger which breeds on the coasts and islands of the North Atlantic in northern Europe and northeastern Nort ...

(''Larus marinus''), small clutch Image:Masked Lapwing Eggs.jpg,

Masked lapwing The masked lapwing (''Vanellus miles'') is a large, common and conspicuous bird native to Australia (particularly the northern and eastern parts of the continent), New Zealand and New Guinea. It spends most of its time on the ground searching for ...

(''Vanellus miles''), typical clutch Image:Waterhoennest.JPG,

Common moorhen The common moorhen (''Gallinula chloropus''), also known as the waterhen, is a bird species in the Rail (bird), rail family (Rallidae). It is distributed across many parts of the Old World, across Africa, Europe, and Asia. It lives around well-ve ...

(''Gallinula chloropus''), small clutch Image:Aquila pomarina nest with eggs.jpg,

Lesser spotted eagle The lesser spotted eagle (''Clanga pomarina'') is a large Eastern European bird of prey. Like all typical eagles, it belongs to the family Accipitridae. The typical eagles are often united with the buteos, sea eagles, and other more heavy-set Ac ...

(''Aquila pomarina''), typical clutch Image:Columba livia nest 2 eggs.jpg,

Feral pigeon Feral pigeons are birds derived from domesticated populations of the rock dove ''Columba livia'', descendants that have escaped and are living independently from (and often unwanted by) humans, having gone "feral". They are sometimes given the ...

(''Columba livia domestica''), typical clutch Image:Starling eggs.jpeg,

European starling The common starling (''Sturnus vulgaris''), also known simply as the starling in Great Britain and Ireland, and as European starling in North America, is a medium-sized passerine bird in the starling family, Sturnidae. It is about long and ha ...

(''Sturnus vulgaris''), typical clutch Image:Stieglitzgelege.jpg,

European goldfinch The European goldfinch or simply the goldfinch (''Carduelis carduelis'') is a small passerine bird in the finch Family (biology), family that is native to the Palearctic zone in Europe, northern Africa, and western Asia. It has been introduced t ...

(''Carduelis carduelis''), large clutch Image:DesmognathusFuscusPageVA.jpg,

Northern dusky salamander Northern may refer to the following: Geography * North, a point in direction * Northern Europe, the northern part or region of Europe * Northern Highland, a region of Wisconsin, United States * Northern Province, Sri Lanka * Northern Range, a ra ...

(''Desmognathus fuscus''), typical egg clutch

References

{{reflist, 30em Birds Bird breeding Aviculture Oology

Size

Gallery

See also

References